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In This Issue

1  Apologies
2  Welding Circuit Problem
4  Featured Product- Postalloy® 2813 SPL
5 Humor: 1957 Statements

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Apologies

Looks like I goofed again. Sometimes this cyber stuff can get to you. If you didn't receive the first issue of Volume 4, which was supposedly sent out February 2, 2004, it is most likely that my program for mass mailing failed to complete the task. I have since found the problem, and of course it was my fault. Sometimes running 2 versions of the same program on your machine doesn't work very well. I had to go into the Register and delete the conflicting files. Very touchy when you fool with the Register. Anyway, my apologies for missing you. You can find the Volume 1 Issue 1 at http://www.postle.com/Newsletter/V4_1/vol4issue1.htm. This Issue dealt with Tip and Feedability of hardfacing wires and showcased Postalloy® 2828 FCO, a titanium carbide wire.
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Welding Circuit Problem

I'm bringing this up for discussion because I recently encountered an application involving weld deposit failures that were traced back to the power supply settings. The application involved a change from a manual or semi-automatic process to an automatic process. The problem became very apparent after spalling of the deposit was encountered after the change was made. Of course, the wire was blamed until after a careful investigation was conducted the problem revealed a voltage issue. Let me explain.

Arc voltage is normally measured across the terminals of the power supply and displayed on a meter housed in the machine. Adjusting the knob up or down usually results in a visual change in the arc or arc length. I won't go into all the aspects of voltage variations in hardfacing now. I'll save that as a separate topic. What I want to focus on is, what are we really measuring across those two terminals. The illustration below shows the basic welding layout of power supply, welding gun and work piece, all connected by welding cable. Click on the Blue Button to check out the areas of resistance in a welding circuit.

Once the voltage is set, the amount of current flowing in the circuit is governed by the resistance of all the components in the circuit. That means, the resistance of the cables, any electrical connections, the work piece and of course the actual Arc. Please note that the Arc is only one component in the circuit.

Now let's take a closer look at the application and the change to the automatic operation. First, the application was open arc or gasless. Second, both the power supply and wire feeder were moved to the automatic setup. The dial settings for Voltage and Wire Feed were marked on the housings for ideal operation and easy replication. So, we have the same equipment in both cases. Third, 4/0 cables replaced the 2/0 cables of the manual setup. Fourth, new grounds were installed. After all installation measures were taken, the Voltage and Wire Feed knobs were returned to the their respective markings on the housings. When the arc was struck and the beads deposited, all appeared to be OK. However, when Quality Assurance checked the hardness, it was way off and subsurface porosity was noted. WHAT HAPPENED???????

Going back to our diagram above. Remember, I said that the current flowing in the circuit is governed by the resistance of each component. By replacing the 2/0 cable with 4/0 cable, the total cable resistance lowered . The new grounding was an improvement over the old ground and its resistance was also lowered. We also discovered that the power supply was a lot closer to the work, which also lowered the cable resistance. All these improvements were great but the electrical circuit was not anywhere near the old circuit. With the automatic setup, there was less resistance, which led to more current and a longer arc length. The arc length was a subtle change and because a welder was not physically attached to the gun, it was overlooked and no adjustments were made.

So where did the porosity come from and why was the hardness low? All cored wires have a "Voltage Tolerance". Which means they can operate between a low and high value of Arc Voltage or Arc Length. At the low end of the Tolerance limit, the wire stubs out, and at the high end the Tolerance limit, the arc pumps nitrogen from the atmosphere into the puddle and creates subsurface porosity. Most open arc wires have from 6 to 8 volts of tolerance. The manual operation was at the high end of the Tolerance limit, and OVER the Tolerance limit in the automatic operation. Thus the porosity. The low hardness readings were faulty because of the porosity and somewhat affected by the increased dilution due to the higher current.

The problem immediately went away when adjustments were made for the new circuitry. The lesson learned here was invaluable; any changes in the electrical weld circuit can have profound effects in the deposit integrity.
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Featured Product - Postalloy® 2813 SPL

Humor - 1957 Statements

In reading these, it struck me how things, or at least the issues, really haven't changed that much, but the prices sure have. Probably most of you will not remember 1957, but I hope you enjoy the humor.

The following are comments made in the year 1957:

(1) "I'll tell you one thing, if things keep going the way they are, pretty soon $20.00 won't even buy a week's groceries!"

(2) "Have you seen the new cars coming out? It won't be long when $5,000 will only buy a used one."

(3) "If cigarettes keep going up in price, I'm going to quit. A quarter a pack is ridiculous."

(4) "Did you hear the post office is thinking about charging a dime just to mail a letter?"

(5) "If they raise the minimum wage to $1, nobody will be able to hire outside help."

(6) "When I first started driving, who would have thought gas would cost 29 cents a gallon. Guess we'd be better off leaving the car in the garage,"

(7) "Kids today are impossible. Next thing you know, boys will be wearing their hair as long as the girls,"

(8) "I'm afraid to send my kids to the movies any more. Ever since they let Clark Gable get by with saying damn in "Gone With The Wind", it seems every new movie has either hell or damn in it."

(9) "Did you see where some baseball player signed a contract for $75,000 a year just to play ball? It wouldn't surprise me if someday that they will be making more than the President."

(10) "I never thought I'd see the day all our kitchen appliances would be electric. They are even making electric typewriters now."

(11) "I'm just afraid the Volkswagen car is going to open the door to a whole lot of foreign business."

(12) "Thank goodness I won't live to see the day when the Government takes half our income in taxes. I sometimes wonder if we are electing the best people to Congress."

(13) "The drive-in restaurant is convenient in nice weather, but I seriously doubt they will ever catch on."

(14) "I guess taking a vacation is out of the question nowadays. It costs nearly $15.00 a night to stay in a hotel."

(15) "No one can afford to be sick any more, $35.00 a day in the hospital is too rich for my blood."